<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Mi</title>
    <style>
        .logo_box{
            background-color: #ff6700;
            width: 49px;
            height: 49px;
            margin: 100px auto;
            position: relative;
            overflow: hidden;
        }
        /*表示mi.png*/
        .logo::before{
            content: '';
            display: block;
            width: 49px;
            height: 49px;
            background-image: url("img/mi-logo.png");
            position: relative;
            top: 0;
            left: 0;
            transition: left 0.3s ;
        }
        .logo::after{
            content: '';
            display: block;
            width: 49px;
            height: 49px;
            background-image: url("img/mi-home.png");
            position: absolute;
            top: 0;
            left: -49px;
            transition: left 1s ;
        }
        .logo_box:hover .logo::before {
            left: 49px;
        }
        .logo_box:hover .logo::after {
            left: 0;
        }

    </style>
</head>
<body>
<div class="logo_box">
    <a href="#" class="logo"></a>
</div>
</body>
</html>